Glucocorticoid receptor in human placenta: Studies of concentration and functional differences of preterm and term tissue

Jean M. Lageson, Thomas C. Spelsberg, Carolyn B. Coulam

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

Glucocorticoids have been suspected of being a factor in premature parturition. This study identifies and characterizes a glucocorticoid receptor in human placentas at various gestational ages. Placental segments in culture translocate 3H-labeled steroid to the nucleus. Scatchard analysis of placental cytosol reveals a relatively high-affinity (dissociation constant = 10-8) and low-capacity binding of dexamethasone to a protein. An 8S-to-4S shift with low-to-high salt treatments is shown by sucrose density gradient analysis. The binding protein is precipitated by 35% ammonium sulfate. This ammonium sulfate fraction of cytosol displays a steroid specificity and a capacity of the receptor to bind to nuclear acceptor sites in cell-free assays. Thus, the presence of a glucocorticoid receptor is supported. A sevenfold to twelvefold increase in concentration of receptor was found between samples of placental tissue from the first and second trimesters; no significant difference was detected between the second and third trimesters. The capacities of the "receptors" from mature and premature placental tissues to bind to chromatin were not markedly different; thus, the biologic activities of the receptors among the different trimesters appear equivalent. The placenta thus appears to be a target tissue for glucocorticoids. The pronounced differences in receptor concentrations in placentas from different trimesters may reflect differential responsiveness of the organ to the systemic steroid.

Original languageEnglish (US)
Pages (from-to)515-523
Number of pages9
JournalAmerican journal of obstetrics and gynecology
Volume145
Issue number4
DOIs
StatePublished - Feb 15 1983

ASJC Scopus subject areas

  • Obstetrics and Gynecology

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